Note: Descriptions are shown in the official language in which they were submitted.
-
AEROSOL-PRODUCING FIR~ EXTINGUISHANT
The present invention relates to extinguishing of fires
and, more particularly, to an aerosol-producing fire extingui-
shant.
Widely known in the prior art is fighting the fires with
water. Water remains the basic and the cheapest material for
fire control. To augment its effect, water is saturated with
carbon dioxide, with dissolved carbonates and other salts of
alkali metals, and mixed with other chemicals. Thus, there is
a known anticorrosive extinguishant containing water, potassium
carbonate, boron or a boron-containing compound and potassium
salt of an organic acid (US, A, No. 4756839).
However, the sphere of application of water and aqueous
solutions for fire control is limited. For example, the use of
these substances if impermissible for fighting a fire on an
object provided with electrical wiring.
One of the most universal fire-fighting means nowadays
are powdered compositions.
Of these the most popular ones are fire-extinguishing pow-
ders based on phosphorus-ammonium salts, sodium carbonates and
bicarbonates, sodium and potassium chlorides (SU, A,
No. 1459669, SU, A, No. 1456171, US, A, No. 3985658, JP, B,
No. 64-9869, etc.).
The mechanism of fire extinguishing may vary depending
on the type of powder used. The fire can be suppressed by phy-
sical or chemical means, or both simultaneously.
The fire-extinguishing powders can be used universally
when dealing with various kinds of burning mechanical and elec-
trical equipment~ etc. when water and other means are useless
- 2 - 2 ~ ~ 9 9 ~ ~
or impermissible. Besides, fire-extinguishing powders are of
low toxicity or nontoxic altogether, and can be used within a
broad range of temperatures.
However, fire-extinguishing powders are noted for a high
tendency to saturation with water, caking and lumping and have
a comparatively high fire-suppressing concentration (1.4-1.8
kg/m2 ) .
Besides, the highest fire-extinguishing effect of these
powders is attained at a high dispersity of their particles
(about 1 micron) which involves certain complication in produ-
cing the powder of a requisite dispersity and increases its
cost.
The aerosol-producing fire-extinguishant approaching most
closely the claimed invention is the extinguishant (US, A
No. 3972820) which is a solid mixture consisting of 3-50 wt.%
of combustible binder (epoxy resin), 15-45 wt.-% of oxidant
(sodium or potassium chlorates or perchlorates) and 25-85 wt.%
of fire-extinguishing agent.
The fire-extinguishing agent consists of haloid compounds
such as hexachlorobenzene, hexabromobenzene, perchlorpentacyc-
lodecane, dibromotoluene, 1,2,3,4-tetrachlorobromobutane, tet-
rabromo-x-diethylbenzene, etc.
The fire-fighting practice employing said known extin-
guishant is based on a radically different approach. During
combustion of this compound. The source of fire is acted upon
by a sublimated and sprayed haloid compound which features a
fire-inhibiting effect.
This extinguishant ensures a higher fire-extinguishing
2 0 $ ~ 9 Q ~
efficiency and is devoid of the drawbacks inherent in water,
aqueous solutions and fire-extinguishing powders.
However, inasmuch as this known extinguishant contains
haloid compounds (e.g. hexachlorobenzene, etc.), the products
of its decomposition comprise halogen derivatives which are,
essentially, volatile, toxic and chemically aggressive. These
properties of the decomposition products of said known fire-
extinguishant bring about a danger of intoxication of person-
nel that happen to be in close proximity to the fire and cause
undesirable corrosion of equipment located in the burning ob-
ject. In addition, the halogen derivatives destroy the ozone
layer of the atmosphere and their use is, therefore, being now
drastically curtailed.
The main object of the invention is to provide an aerosol-
producing fire extinguishant containing such chemical compo-
nents which, being decomposed, would liberate nontoxic and ozo-
ne-safe chemical substances featuring a high fire-fighting ef-
fect.
This object is attained in an aerosol-producing entingui-
shant containing an oxidant and a combustible binder which, ac-
cording to the invention, contains potass;um nitrate as an oxi-
dant, plasticized nitrocellulose as a combustible binder and,
additionally, carbon as a decomposition activator of potassium
nitrate. These components are used in the following proporti-
ons, wt.-~:
Potassium nitrate - 40-70
Carbon - 5-15
Plasticized nitrocellulose - 15-55
.~
2~8~Q~I
-- 4
It is practicable that the plasticized nitrocellulose
should consist of diethyleneglycoldinitrate or triethylenegly-
coldinitrate or a mixture thereof in any mass proportion, the
mass proportion of nitrocellulose and plasticizer being from
40-50 to 60-50, respectively.
The nitrocellulose plasticizer may be constituted by tri-
acetin with a nitrocellulose-plasticizer mass proportion of
45-68 and 55-32, respectively.
To enhance chemical stability of the aerosol-producing
extinguishant and to enable its use at elevated temperatures,
it is expedient that it should contain additionally 0.5-3.0
wt.-% of a chemical composition stabilizer.
It is practicable that the chemical composition stabili-
zer should be represented by N,N'-diethyl-N,N'-diphenylurea or
N,N'-dimethyl-N,N'-diphenylurea or diphenylamine.
It is preferable that the chemical composition stabilizer
should be a mixture of diphenylamine with N,N'-diethyl-N,N'-
diphenylurea or with N,N'-dimethyl-N,N'-diphenylurea in any
mass proportion.
To ensure rheological and mechanical characteristics of
the aerosol-producing fire-extinguishant enabling it to be mol-
ded into products of various shape and size, it is practicable
that it should contain an auxiliary addition in the amount of
0.02-3.35 wt.-% of the total mass of the extinguishant.
To reduce specific external friction during preparation
of the aerosol-producing extinguishant it is preferable that
the auxiliary addition should be lubricating oil in the amount
of 0.5-2.5 wt.% of the mass of the extinguishant.
It is also possible for reducing specific external fric-
tion to use the salt of stearic acid in the amount of 0.02-
0.50 wt.-% of the mass of the extinguishant.
It is preferably that the salt of stearic acid should be
constituted by sodium stearate or zinc stearate or a mixture
thereof in any mass proportion.
With the same object in view it is preferable that the
auxiliary addition in the extinguishant should contain a mixtu-
re of lubricating oil and salt of stearic acid in the amount
of 0.5-2.5 wt.-% and 0.02-0.50 wt.-%, respectively, of the mass
of extinguishant.
To ensure uniform distribution of components, reduce the-
ir mixing time and cut down the specific external friction in
the course of extinguishant production, it is practicable that
the auxiliary addition should be constituted by a mixture of
lubricating oil, salt of stearic acid and sulfonated castor oil
in the amount of 0.5-2.5 wt.-%, 0.02-0.50 wt.-% and 0.02-0.30
wt.-%, respectively, of the mass of extinguishant.
With the same purpose in view it is also possible that
the auxiliary addition of the extinguishant should contain a
mixture of lubricating oil, salt of stearic acid and gelatin
in the amounts of 0.5-2.5 wt.-%, 0.02-0.5~0 wt.-% and 0.01-0.05
wt.-%, respectively, of the mass of extinguishant.
It is also practicable that the auxiliary addîtion of
the extinguishant should contain a mixture of lubricating oil,
a salt of stearic acid, sulfonated castor oil and gelatin ta-
ken in the amount of 0.5-2.5 wt.-%, 0.02-0.50 wt.-%, 0.02-0.30
wt-%, and 0.01-0.05 wt.-%, respectively, of the mass of extin-
guishant.
To ensure the requisite rheological and mechanical pro-
perties of the aerosol-producing extinguishant when it contains
a large amount of disperse additions, it is preferable that it
contain additionally 1-10 wt.-% of polyvinylacetate in the ca-
pacity of combustible binder.
It is most preferable that the amount of polyvinylacetate
should be 1-5 wt.-% of the mass of extinguishant.
The claimed aerosol-producing fire-extinghishant ensures
high efficiency of fire fighting, rules out the danger of in-
toxication of the personnel in close proximity to the site of
fire-fighting activities, eliminates corrosion of equipment
and destructive effect on the ozone layer of the atmosphere.
Apart from that, the oxidant in the claimed extinguishant ser-
ves, essentially, as a source of fire extinguishant. This pro-
vides for a substantial reduction of the volume of the article
made of said extinguishant, required to protect a unit volume
of the burning object and, consequently, enables using compact
aerosol generators for fire control.
Now the invention will be described by way of concreté
examples of its realization.
The aerosol-producing fire extinguishant according to the
invention contains an oxidant, a combustible binder and an ac-
tivator of oxidant decomposition.
The oxidant is potassium nitrate and the combustible bin-
der is plasticized nitrocellulose. The decomposition activator
of potassium nitrate is earbon.
The components of the extinguishant are taken in the fol-
lowing proportions, wt.%:
Potassium nitrate - 40-70
Carbon - 5-1~
Plasticized nitrocellulose - 15-55
The process of decomposition of the disclosed aerosol-
producing fire extinguishant and formation of aerosol may be
expressed in a general form by the following chemical reaction:
a~CnHmNpOq + b*C ~ c*KN03 = d~C02 + e*H20 + f*N2 + s*KOH +
h~K20 + k*K2C03 ( 1 ),
which forms gaseous (C02, H?O, N2) and highly-dispersed (KOH;
K20; K2C03) condensed products, i.e. aerosol. At a combustion
temperature the potassium compounds are in a dissociated
state and the combustion products contain potassium ions.
It can be seen from the above chemical reaction that, as
distinct from all previously known aerosols, the claimed aero-
sol contains no toxic and ozone-destroying sugstances.
Due to the presence of potassium ions in the combustion
products of the aerosol-producing fire extinguishant, the clai-
med aerosol features high fire-inhibiting characteristics and,
when delivered to the center of a fire, suppresses the chain
reaction$ of combustion, such as:
Oxidation of hydrogen Combustion of carbon
oxide (in presence of hydrogen)
H2 ~2 20H H2 ~2 20H
OH + H2 = H20 + H OH + CO = C02 + H
+ ~2 = OH + O H + ~2 = OH + O
O + H2 = OH + H O + H2 = OH + H
-- 8
Inhibition, Chain Stopping
OH + K = KOH OH + K = KOH
The fundamental characteristic of the fire extinguishant
is its fire-fighting efficiency, defined by a minimum mass of
the component required for quenching a fire in 1 m3 of air
(fire-extinghishing concentration M). The lesser the value of
M, the higher is the fire-extinguishing efficiency of the ex-
tinguishant.
To achieve a high fire-extinguishing efficiency, the aero-
sol shall be highly-dispersed with potassium ion in the combus-
tion products of the extinghishant. The potassium nitrate pre-
sent in the extinguishant should decompose completely in the
course of burning. This is ensured by using a highly-dispersed
carbon (specific surface of 80-100 m2, approximately) which
serves as a decomposition activator of potassium nitrate and
at the same increases the viscosity of the burning layer and
keeps potassium nitrate on the burning surface of the fire ex-
tinguishant, ensuring thermal decomposition of this salt.
The higher the content of potassium nitrate in the fire
extinguishant, the larger amount of carbon should be added to
it. However, it is not expedient to introduce more than 70%
of potassium nitrate into the extinguishant since this will
require a large amount of carbon for complete decomposition of
potassium nitrate during combustion. The total content of dis-
persed additions in the extinguishant exceeding 85% (over 70%
of potassium nitrate and over 15% of carbon) bears an adverse
effect on the mechanical and rheological properties of the ex-
tinguishant. Deterioration of the mechanical properties of
extinguishant involves simultaneous reduction of its strength
- - 9
and deformation caused by a low content of binder. Worsening
of the technological properties is expressed by higher values
of specific external friction and a low flowability of the ex-
tinguishant at elevated temperatures at which the compound is
molded into products. In this case the molding press cannot
overcome the resistance of the compound so that molding of
fire-extinguishing products is rendered difficult or altogether
impossible. This combination of mechanical and rheological pro-
perties of the extinguishant makes it poorly manufacturable,
difficult to extrude and steps up considerably the cost of the
products made from it due to higher power expenditures for mol-
ding.
A lower content of potassium nitrate in the fire-extin-
guishant reduces its combustion-inhibiting properties and,
consequently, its fire-extinguishing efficiency. Besides, if
its content is under 40 wt.-% and, consequently, that of car-
bon is below 5 wt.-%, the ignitability and combustion stabili-
ty of the extinguishant suffer tool.
The considered compositions of the claimed extinguishant
are heavily-loaded ones wherein the binder is nitrocellulose
which should be plasticized as a mandatory requirement.
If the nonplasticized nitrocellulose is used, the process
of extinguishant combustion will proceed not over the surface,
as is the case with plasticized nitrocellulose, but in a volu-
metric space, which will result in explosive burning.
The nitrocellulose-to-plasticizer ratio and the amount
of plasticized cellulose influence the complex of mechanical
and technological properties of the fire extinguishant and ha-
-
-- 10 --
ve to suit its purpose and application, i.e. to comply with
the requirements of mechanical strength, rheological and other
properties.
The mechanical strength of the fire extinguishant increa-
ses with the growing content of plasticized nitrocellulose and
drops when the content diminishes.
However, it is inexpedient to raise the content of plas-
ticized nitrocellulose in the compound in excess of 55 wt.-%
by reducing the content of potassium nitrate and carbon below
40 and 5 wt.-%, respectively, since it would not ensure high
efficiency of the extinguishant.
Introducing into the compound less than 15 wt.-% of pla-
sticized nitrocellulose (in absence of an additional binder)
fails to provide the required mechanical and technological pro-
perties of the extinguishant, as has been described above.
The plasticizers of nitrocellulose may be constituted by
diethyleneglycoldinitrate, triethyleneglycoldinitrate or mix-
tures thereof, or triacetin.
The optimum amount of each type of plasticizer with rela-
tion to nitrocellulose, depending on its plasticizing capacity
is selected experimentally.
With respect to the complex of their chemophysical pro-
perties and plasticizing capacity with relation to nitrocellu-
lose, diethyleneglycoldinitrate and triethyleneglycoldinitrate
are identical and can, therefore, be either interchangeable or
used jointly in any mass proportions.
When the plasticizer consists of diethyleneglycoldinitrate,
triethyleneglycoldinitrate or mixtures thereof, these compo-
nents are used in the following proportion, wt.-% of the
mass of plasticized nitrocellulose:
nitrocellulose 40-50
diethyleneglycoldinitrate or
triethyleneglycoldinitrate,
or a mixture thereof 60-50
If in this case the amount of introduced plasticizer ex-
ceeds 60 wt.-% of the mass of plasticized nitrocellulose, the
viscosity of the compound diminishes substantially and flow-
ability of the compound increases sharply. This affect adver-
sely the rheological characteristics of the compound. In par-
ticular, the shearing stress of the compound diminishes radi-
cally. It becomes so low as to bring about difficulties in
molding the products from the compound. For example, the com-
pound may stop moving in the course of molding in a screw
press.
When the amount of plasticizer is less than 50 wt.-% of
the mass of plasticized nitroceullulose, the extinguishant
becomes too viscous. This likewise impairs the rheological
characteristics of the composition and causes complications
in reprocessing the mass, as has been described above.
When triacetin is used for plasticizer, nitrocellulose
and triacetin are taken in the following relations, wt.-% of
the mass of plasticized nitrocellulose:
nitroceullulose 45-68
triacetin 55-32
These relations are optimum for triacetin on the basis
of the same reasoning as that used when selecting the ratios
-
- 12 -
for the above-described plasticizers.
It is practicable that the composition be treated with
various chemical composition stabilizers whose effect is
based on fixing the nitrogen oxides if they are liberated for
some reason in the course of preparation and employment of the
fire-extinguishant at elevated temperatures.
The chemical stabilizer may be constituted by N,N'-di-
methyl-N,N'-diphenylurea or N,N'-diethyl-N,N'-diphenylurea or
diphenylamine, or mixtures thereof.
To ensure chemical stability of the composition it is
usually sufficient if the content of the chemical stabilizer
in the compound varies from 0.5 to 3.0 wt.-~ of its total
mass.
The concrete material used as chemical stabilizer of the
extinguishant, and its quantity, are selected to suit the pros-
pective application of the extinguishant.
For fixing nitrogen oxides during reworking of the com-
pound at elevated temperatures, it is practicable to use cent-
ralite while thermal stability during prolonged service will
~e ensured by a mixture of centralite with diphenylamine.
If the fire extinguishant is used in station~ry fire-
fighting appliances not subjected to the effect of elevated
temperature (e.g. in garages, storehouses, etc.) it is suf-
ficient to add about 0.5 wt.-~ of centr~lite or diphenylamine
or a mixture thereof. When the extinguishant is used in fire-
prevention equipment of motor vehicles where temperature under
the enginer hood may rise to 50~C and higher, it is expedient
! E~.
- 13 -
that the chemical stabilizer be constituted by a mixture of
centralite with diphenylamine in the amount of 1 wt.-% and
over. However, it is not expedient to use more than 3 wt.-%
of chemical stabilizer since large quantities of centralite
and diphenylamine may exert a decomposing influence on nitro-
cellulose, resulting in a contrary effect.
Besides chemical stabilizers when used in large quantiti-
es, become ballast substances which reduce the oxygen content
in the extinguishant and impair combustion characteristics.
The amount of chemical stabilizer in the ex-tinguishant
below 0.5 wt.-% is little effective.
When there is a large amount of dispersed additions (mo-
re than 65 wt.-% of potassium nitrate and carbon taken toge-
ther), the requisite mechanical and rheological characteristics
of the extinguishant will be obtained by introducing polyvinyl-
acetate (PVA) as an additional binder which wi]l enhance vis-
cosity and mechanical strength of the compound.
For example, at a content of 60 wt.-% of potassium nitra-
te and 11 wt.-% of carbon the tensile strength of the extin-
guishant at 20~C is as follows:
w/o PVA 1 MPa
2% PVA 1.5 MPa
5% PVA 2.0 MPa
10% PVA 2.5 MPa
Introduction of PVA into a fire-extinguishant heavily
loaded with potassium nitrate and carbon improves rheological
characteristics which is evidenced by an increased shearing
stress due to a higher viscosity of the system.
- 14 -
In case of more than 10 wt.-~ of PVA in the extinguishant
from the mass of the compound, viscosity of the latter rises
considerably thus increasing sharply the specific external fric-
tion and, consequently, causing complications in molding the
products as has been stated above.
If the PVA content in the compound is less than 1 wt.-
~of the compound, its binding effect is insignificant.
The preferable amount of PVA is up to 5 wt.-~.
The required rheological and technological properties of
the fire-extinguishant (specific external friction, shearing
stress, viscosity characteristics, etc.) are ensured by the
use of various additions introduced either independently or
jointly.
The technological (conventional) additions reducing
specific external friction are lubricating oils and salts of
fatty acids, e.g., stearates of sodium or zinc. Stearates of
various metal are identical both in their chemical structure
and the complex of their chemophysical properties, so that in
the compositions of extingh;sh~nt they may be interchanged or
used jointly in any proportions without changes of all their
characteristics.
For the same reasons, various kinds of lubricating oils
are also interchangeable.
The content of salts of fatty acids and of lubricating
oils in the extinguishant exceeding 0.5 wt.-~ and 2.5 wt.-~,
respectively, of the mass of extinguishant impairs cohesion
and adhesion of components. Simultaneously, the mechanical
strength of the compound and its deformation characteristics
are also impaired.
~.
Q ~ ~
The content of salts of fatty acids and of lubricating
oils in the extinguishant below 0.02 wt.-% and 0.5 wt.-~, res-
pectively, of the mass of extinguishant is insufficient for the
reduction of specific external friction.
The additions aimed to ensure uniform distri~ution of all
extinguishant components and to reduce their mixing time are
constituted by surfactants such as sulfonated castor oil (sul-
foricinate) and gelatin in the amounts of 0.02-0.3 wt.-~ and
0.01-0.05 wt.-~ of the mass of extinguishant, respectively.
The content in the extinguishant of sulforicinate in ex-
cess of 0.3 wt.-~ and of gelatin in excess of O.OS wt.-% re-
sults in heavy foaming and in more difficult pressing of all
components from the aqueous medium in which they are usually
mixed according to the below-described process.
The content of sulforicinate below 0.02 wt.-% and of ge-
latin below 0.01 wt.-% of the mass of extinguishant is insuffi-
cient for uniform distribution of all components in the extin-
guishant compositions.
The extinguishants employed in fire-fighting practice ha-
ve the form of monolithic ~olded products located in the fire
extinguisher, i.e. in an aerosol generator.
The extinguishant according to the invention is prepared
as follows.
All the components except potassium nitrate are mixed in
certain proportions in a mixer of any kind providing uniform
mixing thereof.
For more homogeneous mixing, the components may ~e mixed
in an aqueous medium in presence of such surfactants as sulfor-
- 16 -
icinate and gelating.
After mixing of all components in the aqueous medium the
resulting homogeneous mixture is pressed away from water on
filtering installations such as a centrifuge or squeezing
press.
The homogeneous mixture of extinguishant components pres-
sed away from water or produced by dry mixing is mixed in ap-
paratuses having no mechanical agitators (where the material
is mixed due to rotation and vibration of the apparatus around
its own axis) or by other methods with potassium nitrate than
molded into products of any size and shape by the method of
straight-through pressing on a hydraulic press or screw extru-
der.
All the components including potassium nitrate may also
be mixed in an apparatus without mechanical agitators followed
by molding of articles as described above.
The process of molding products on a hydraulic press or
a screw extruder is widely known to those skilled in the art
and calls for no detailed description.
The product made of the claimed extinguishant is placed
into an aerosol generator which is installed in the space to
be protected and functions automatically. The igniter provided
in the generator ignites the article made of the extinguishant.
Combustion proceeds according to a chemical reaction (1) and
produces aerosol discharged from the generator at a high velo-
city. Aerosol fills up the protected space, reaches the source
of fire and stops the chain reactions of combustion.
The mass of extinguishant and the number of aerosol ge-
nerators are calculated on the basis of the volume of the pro-
tected object, the fire-extinguishing capacity of the aerosol-
producing extinguishant, design of the generator and the safe-
ty margin of 1.2-2Ø
The invention will be better ellucidated by the examples
cited below.
EXAMPLE 1
The ratio of extinguishant components was selected from
the data of Table 1.
Table 1
Component Ratio of components, wt.-%
Potassium nitrate 50
Carbon 10
Nitrocellulose 18
Plasticizer:
mixture of diethylenegly-
coldinitrate and triethy-
leneglycoldinitrate 22
(70:30 wt.-%)
Nitrocellulose-to-plasti-
cizer ratio 45/55
Nitrocellulose was mixed in an aqueous medium with a mix-
ture of diethyleneglycoldinitrate with triethyleneglycoldinit-
rate and carbon at a module 1:5, T = 20+5~C in the course of
18 h approximately. Then the resulting mixture was pressed away
9 ~ ~
- 18 -
from water on a squeezing apparatus to a moisture content of
15% approximately and mixed with potassium nitrate for 20 min.
The ready mixture was delivered into a hydraulic press for
molding at T = 80 - 85~C and a pressure of about 15 MPa into
products of 15-mm diameter of various length and, consequently,
of different mass. Then the minimum fire-extinguishing concen-
tration M of the extinguishant was determined. The value of M
was found as follows:
A bowl containing 40 ml of gasoline with a surface area
of 63 cm2 was placed into a 85-l chamber. Then the time of na-
tural burning-out of gasoline (35 s) was determined. Next, a
2.5 g specimen of aerosol-producing extinguishant was placed
into the chamber. Gasoline was ignited in the bowl and, 5 s af-
ter ignition of gasoline, the specimen of extinguishant was ig-
nited. Burning gasoline was extinguished in the bowl within
2 s. The specimen failed to burn up completely within this time.
Extinguishing of flame within not longer than 5 s after comple-
te burning up of the extinguishant specimen was considered to
be a positive result. Concentration was 30 g/m3.
The experiment was repeated with a specimen weighing
2.2 g. Gasoline flames in the bowl were extinguished concurrent-
ly with burning-up of the extinguishant specimen. Concentration
was 27 g/m3.
In the case of a specimen weighing 1.7 g, gasoline fire
was extinguished in the bowl 8 s after burning-up of the spe-
cimen.
Thus, the minimum fire-extinguishing concentration M of
the extinguishant was determined by changing the weight of its
-- 19
specimens. At this m:inim-Jm concentration the flames were quen-
ched within 5 s after the b-urning-up of the specimen. The va-
lue of M was 26 g/m3.
The experiment was repeated under identical conditions
but gasoline was replaced by acetone, ethyl alcohol and iso-
propyl alcohol. The results of extinguishing of flammable li-
quids were analogous to those obtained with gasoline. The value
of M was 26 g/m3.
EXAMPLE 2-5
All the conditions of Example 1 were fully complied with
in Examples 2-5 but the ratios of components were taken into
Table 2. The values of minimum fire-extinguishing concentrati-
ons M of extinguishants were determined as in Example 1:
Table 2
Component ratio, wt.-%
Component
Example No.
2 3 4 5
1 2 3 4 5
Potassium nitrate 40 70 38 72
Carbon 5 15 4 17
Nitrocellulose 27.5 6 29 4.4
Plasticizer:
mixture of diethyleneglycol-
dinitrate and triethylene-27.5 9 29 6.6
glycoldinitrate (70:30 wt.-%)
- - 20 - ~ ~
Table 2 (cont.)
1 2 3 4 5
Nitrocellulose-to-plasticizer
ratio 50/50 40/60 50/50 40/60
_______________________________________________~______________
Minimum fire-extinguishing
concentration M, g/m3 46 20 ; ;:;
'; Not determined due to poor ignitability and burning instabi-
lity of extinguishant.
:;'; Specimens were not produced due to insufficient binder con-
tent.
EXAMPLES 6-16
The compositions of aerosol-producing fire-extinguishant
in Table 3 were prepared just as in Example 1. the additional-
ly introduced chemical stabilizers (contralite and diphenylami-
ne) and the technological addition (gelatin) were loaded into
the mixer being mixed in advance with a plasticizer. Such tech-
nological additions as lubricating oil, stearates of metals and
sulforicinate were put into the mixer after introduction of
nitrocellulose. Polyvinylacetate was added after the plastici-
zer. The minimum fire-extinguishing concentration M was deter-
mined as in Example 1 and is also stated in Table 3.
EXAMPLE 17
The ratio of extinguishant components was based on the
data of Table 4.
- 21 -
Nitrocellulose, carbon and triacetin were mixed in "Be-
ken" mixer, the resulting homogeneous mix-ture was mxied with
potassium nitrate in an apparatus without mechanical agitators,
and molded into 15-mm dia pieces as described in Example 1.
The minimum fire extinguishing concentration M determined as
in Example 1 was 27 g/m3.
EXAMPLES 18-21
Compositions of fire extinguishant listed in Table 5 were
made as in Example 17 and molded into 15-mm die pieces as des-
cribed in Example 1. The minimum fire-extiguishing concentra-
tion M was determined as in Example 1 and is also given in
Table 5.
EXAMPLES 22-28
Compositions of fire extinguishant listed in Table 6 we-
re made as in Example 17 and molded into 15-mm dia pieces as
described in Example 1. The additional chemical stabilizers
(centralite and diphenylamine) were dissolved in triacetin.
EXAMPI.ES 6-16
Table 3
Component ratio, wt.-%
Component
Example No.
6 7 8 9
1 2 3 4 5
Potassium nitrate 4055 70 40
Carbon 5 10 15 5
- 22 -
Table 3 (cont.)
1 2 3 4
Carbon 10 4 16
Nitrocellulose 17.17 27.27 2.08
Diethyleneglycoldinitrate 6.3 13.05 1.6
Triethyleneglycoldinitrate 14.7 13.05 1.6
Polyvinylacetate - - 5.1
Centralite 0.3 1.0 0.2
Diphenylamine 0.2 1.0 0.2
Lubricating oil 1.0 2.6 0.4
Sodium stearate 0.05
Zinc stearate 0.05 0.01 0.51
Sulforicinate 0.2 0.01 0.3
Gelatin 0.03 0.01 0.01
Nitrocellulose-to-plasti-
sizer ratio 45/55 51/49 39/61
Minimum fire-extinguishing
concentration, M, g/m3 27 '; *~
* Poor ignitability of extinguishant. Unstable burning under
normal conditions.
** Specimens not obtained due to unsatisfactory rheological
characteristics.
- 23 -
Table 3 (cont.)
Component ratio, wt.-%
Component
Example No.
11 12 13
Potassium nitrate 55 70 50 50
Carbon 10 15 10 10
Nitrocellulose 14.28 4.19 16.47 16.77
Diethyleneglycoldinitrate - - 14.1 10.2
Triethyleneglycoldinitrate 17.4 6.3 6.1 10.2
Polyvinylacetate - 3.0
Centralite - - 1.0 0.7
Diphenylamine 1.5 0.5 1.0 0.8
Lubricating oil 1.5 0.5 1.0 1.0
Sodium stearate - - 0.05 0.05
Zinc stearate 0.1 0.2 0.05 0.05
Sulforicinate 0.2 0.3 0.2 0.2
Gelatin 0.02 0.01 0.03 0.03
Nitrocellulose-to-plasti-
sizer ratio 45/55 40/60 45/55 45/55
______________________ _______________________ ________________
Minimum fire-extinguishing
concentration, M, g/m3 27 20 27 27
- 24 - ~
Table 4
Component Component ratio, wt.-%
Potassium nitrate 63
Carbon 9
Nitrocellulose 16.5
Plasticizer:
triacetin 11.5
Nitrocellulose-to-
plasticizer ratio 58/41
EXAMPLES 18-21
Table 5
Component ratio, wt.-%
Component
Example No.
18 19 20 21
Potassium nitrate 40 70 38 71
Carbon 5 15 4 16
Nitrocellulose 37.4 6.7 39.4 5.8
Plasticizer:
triacetin 17.6 8.3 18.6 7.2
Nitrocellulose-to-
plasticizer ratio 68/32 45/55 68/32 45/55
- - 25 -
Tab]e 5 (cont.)
Component ratio, wt.-%
Component
Example No.
18 19 20 21
Minimum fire-extinguishing
concentration, M, g/m3 45 25 * **
'; Not determined due to poor ignitability of extinguishant
-';'; Specimens not obtained due to unsatisfactory rheological
characteristics.
EXAMPLES 22-28
Table 6
Component ratio, wt.-%
Component
Example No .
22 23 24 25
1 2 3 4 5
Potassium nitrate 40 55 63 70
Carbon 5 9 10 15
Nitrocellulose 34.33 19.8 13.23.9
Triacetin 16.15 12.1 8.8 4.7
Polyvinylacetate - 1.0 2.0 5.0
Centralite - 0.5 0.5 0.5
Diphenylamine 2 1.5 0.5 0.2
f~
- 26 -
Table 6 (cont.)
1 2 3 4 5
Lubricating oil 2.5 1.0 1.5 0.5
Sodium stearate - - 0.5
Zinc stearate 0.02 0.1 - 0.2
Nitrocellulose-to-
plasticizer ratio 68/32 62/38 60/40 45/55
Minimum fire-extinguishing
concentration, M, g/m3 46 35 26 20
Table 6 (cont.)
Component ratio, wt.-%
Component
Example No.
26 27 28
1 2 3 4
Potassion nitrate 60 38 72
Carbon 10 4 16
Nitrocellulose 8.1 36.91 2.46
Triacetin 9.8 16.58 3.13
Polyvinylacetate 40 - 5.1
Centralite 0.5 1.0 0.2
Diphenylamine 0.5 1.0 0.2
Lubricating oil 1.0 2.5 0.4
- 27 -
Table 6 (cont.)
1 2 3 4
Sodium stearate - 0.01 0.51
Zinc stearate 0.1 - -
Nitroceilulose-to-
plasticizer ratio 45/55 69/31 44/56
______________________________________________________________
Minimum fire-extinguishing
concentration, M g/m3 31
' Not determined due to ignitability of extinguishant
~' Specimens not obtained d~e to unsatisfactory rheological
characteristics.
The technological additions (lubricating oil, stearates of
metals) were put into a mixer after introduction of nitrocellu-
lose. Polyvinylacetate was added into the mixer after plastici-
zer. The minimum fire-extinguishing concentration M was deter-
mined as in Example 1 and is also stated in Table 6.
A high fire-extinguishing efficiency of the claimed com-
position (its low minimum fire-extinguishing concentration M)
was confirmed by experimental quenching of the burning engine
of a cargo truck.
EXAMPLE 29
The ratio of components for the fire-extinguishant was
selected from Table 7.
The extinguishant in the form of 48-mm dia 60-g molded
pieces was placed into an aerosol generator.
' ~,
- 28 -
Three aerosol generators were stationed in the engine
compartment of a ZIL-130 cargo truck. The engine was poured
over with gasoline and two 200-mm dia bowls with gasoline were
placed on both its sides. The total amount of gasoline was
400 ml.
Gasoline was put to fire and 10 s later, when gasoline fi-
re was in full blaze, the hood was closed and the extinguishant
pieces were ignited in aerosol generators. After closing the
hood, the light and tongues of flame were seen through the lo-
uvers. On igniting the extinguishant pieces the engine compart-
ment under the hood was filled with a dense white smoke (aero-
sol) which escaped through the louvers. The extinguishant was
burning for 8 s, but flames in the engine compartment were quen-
ched prior to complete burning on the extinguishant. On open-
ing the hood and inspecting the enginer there remained unburnt
gasoline in both bowls.
EXAMPLE 30
The ratio of components was selected from Table 8.
The conditions of experiment were as in Example 29. The
result of the experiment was the same, i.e. the flames were
quenched in the engine compartment of the ZIL-130 truck before
complete burning up of the extinguishant. The bowls contained
unburnt gasoline.
EXAMPLE 31
The ratios of components were the same as in Example 29.
The aerosol-producing fire-extinguishant in the form of molded
pieces of 48 mm diameter, mass 50 g, was placed into an aerosol
generator.
- 29 -
Three aerosol generators were placed into the engine com-
partment of a ZIL-130 truck. The engine was poured over with
gasoline and two 200-mm dia gasoline-filled bowls were put on
either side of the engine. The total amount of gasoline was
800 ml. Motion of the truck was simulated by delivering comp-
ressed air at a pressure of about 0.15 MPa through the radia-
tor. 10 s after igniting galsine, when flames were ablaze,
the hood was closed and the extinguishant pieces in aerosol ge-
nerators were ignited electrically. Like in Examples 29 and 30,
the fire in the engine compartment was put out before complete
burning-up of the extinguishant (extinguishant burning time
was 8 s). Both bowls contained unburnt gasoline.
EXAMPLE 29
Table 7
Component Component ratio, wt.-%
Potassium nitrate 50.0
Commercial carbon 10.0
Nitrocellulose 17.17
Mixture of diethylenegly-
coldinitrate and triethy-
leneglycoldinitrate (ratio 20.0
70:30 wt.-%)
Centralite 0.5
Diphenylamine 0.5
Lubricating oil 1.5
Sodium stearate 0.1
- 30 -
Table 7 (cont.)
Component Component ratio, wt.-%
Sulforieinate 0.2
Gelatin 0.03
EXAMPLE 30
Table 8
Component Component ratio, wt.-%
Potassium nitrate 63.0
Commercial carbon 9.0
Nitrocellulose 14.4
Triaeetin 9.0
Polyvinyl acetate 2.0
Centralite 0.3
Diphenylamine 0.7
Lubricating oil 1.5
Zinc stearate 0.1
Table 9 states the basic characteristies of the aerosol-
produeing fire extinguishants aeeording to the invention. The
level of these eharaeteristies is an evidenee that the claimed
extinguishants ean be sueeessfully made and used for fire-
fighting purposes.
- 31 -
Table 9
Value of characteris-tic
for extinguishant
Characteristie
on nitroester on triacetin
plastieizer
1 2 3
1. Density, kg/m3 1710-1760 1700-1780
2. Physicomeehanical eha
raeteristies
2.1. Tension (T = 293 K)
Ultimate strength, MPa 1-2 1-2.2
Deformation, % 5-10 5-10
Modulus of elas-tieity, MPa 35-80 30-85
? . 2. Compression (T = 293 K)
Ultimate strength, MPa 8-12 8-13
Modulus of elasticity,
MPa 70-100 70-100
2.3. Specific impaet
strength, kJ/kg, at:
(T = 293 K) 10-15 10-15
(T = 223 K) 2.2-3.0 2.3-3.5
3. Design thermodynamie eharae-
teristies at P = 0.1 MPa
(for 40 g of extinguishant
+ 1 m3 of air)*
3.1. Com~ustion temperature,
Tc, K 540 515
_ - 32 -
Table 9 (cont.)
1 2 3
3.2. Composition of eombus-
tion products, wt.-%
~2 21.54 21.56
H20 0.48 0.41
N2 74.63 74.59
C~2 2.26 2.07
K2C03 (eondensed) 1.10 1.38
3.3. Volume of eombustion
produets at T = 293 K,
P = 0.1 MPa, m3/kg 0.790 0.652
4. Minimum fire-exting-lishing
concentration M, g/m3 20-45 20-46
* The design thermodynamic eharaeteristies are given for ex-
tinguishant eompositions of Examples 29 and 30, respectively.
